S3 vs EC2 access speeds (on average)

If we consider that all of our users are located within the same geographic area and that we choose the same location from within either an EC2 instance (running a highly optimized instance type) or an S3 bucket, which would be better for serving content ... EC2 or S3? I have a website that's entirely client driven (running client facing Javascript and is entirely limited in its feature-set) so I'm trying to determine which is the better route. I don't need to save assets nor do I need HTTPS. I realize I can consider CloudFront as well, but let's assume I'm not going to use CloudFront for purposes of this question.